On Sun, Nov 15, 2020 at 05:34:16PM -0700, Nathan Chancellor wrote:
 
> Still good.
> 
> Tested-by: Nathan Chancellor <natechancel...@gmail.com>

Pushed into #fixes

> > BTW, is that call of readv() really coming from init?  And if it
> > is, what version of init are you using?
> 
> I believe that it is but since this is WSL2, I believe that /init is a
> proprietary Microsoft implementation, rather than systemd or another
> init system:
> 
> https://wiki.ubuntu.com/WSL#Keeping_Ubuntu_Updated_in_WSL
> 
> So I am not sure how possible it is to see exactly what is going on or
> getting it improved.

Oh, well...  Anyway, as a regression test it's interesting:

#include <sys/uio.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
main()
{
        static char s[1024];
        static struct iovec v[2] = {{NULL, 0}, {s, 1024}};

        for(;;) {
                ssize_t n = readv(0, v, 2), m, w;

                if (n < 0) {
                        perror("readv");
                        return -1;
                }
                if (!n)
                        return 0;
                for (m = 0; m < n; m += w) {
                        w = write(1, s + m, n - m);
                        if (w < 0)
                                perror("write");
                }
        }
}

which ought to copy stdin to stdout; with this bug it would (on sufficiently
large seq_file-based files) fail with "readv: Bad address" (-EFAULT, that is).

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